Data collection terminal with components mounted on printed circuit boards therein

ABSTRACT

A plurality of printed circuit boards is mounted within a housing of a data collection terminal. The boards lie in respective planes generally parallel to the plane of a top wall of the housing. The boards are spaced apart along an upright direction generally normal to the plane of the top wall. Terminal components are mounted on the circuit boards.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.08/377,998 filed on Jan. 25, 1995, now U.S. Pat. No. 5,532,469, which,in turn, is a division of Ser. No. 08/093,967, filed Jul. 21, 1993, nowU.S. Pat. No. 5,396,055, which, in turn, is a division of Ser. No.07/895,277, filed Jun. 8, 1992, now U.S. Pat. No. 5,262,628, which, inturn, is a division of Ser. No. 07/272,545, filed Nov. 17, 1988, nowU.S. Pat. No. 5,130,520, which, in turn, is a division of Ser. No.07/148,555, filed Jan. 26, 1988, now U.S. Pat. No. 4,845,350, which, inturn, is a division of Ser. No. 06/883,923, filed Jul. 10, 1986, nowU.S. Pat. No. 4,758,717, which, in turn, is a division of Ser. No.06/519,523, filed Aug. 1, 1983, now U.S. Pat. No. 4,673,805, which, inturn, is a division of Ser. No. 06/342,231, filed Jan. 25, 1982, nowU.S. Pat. No. 4,409,470. This application is also related to U.S. Pat.Nos. 4,460,120 and 4,736,095.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a compact printed circuitboard arrangement for use in portable data collection terminals.

2. Description of the Prior Art

Many industries, particularly the grocery and food processing industry,have begun to designate their products with a unique bar code symbolconsisting of a series of lines and spaces of varying widths. Variousbar code readers and laser scanning systems have been developed todecode the symbol pattern to a multiple digit representation forcheck-out and inventory purposes.

Aside from the conventional contact-type and non-contact-type wand orpen bar code readers, true laser scanners, such as point-of-sale or deckscanners of the moving-beam or fixed-beam type, have been built intostationary counters. However, these deck scanners are large, massive,stationary installations. Some symbol-bearing objects are too heavy, toobig, or too inconvenient to be brought to the stationary scanninginstallation. Some objects may be stationary themselves.

In order to provide a mobile scanning system, semi-portable laserscanning heads, such as disclosed in U.S. Pat. No. 4,251,798, weredesigned to permit the user to bring the scanning head to the object.However, such semi-portable heads weighed over three pounds, had to bepartially supported by the object itself, and were too heave andsomewhat difficult to readily manipulate, particularly for thoseassembly-line applications where a user was routinely required torepetitively manipulate the semi-portable head many times per minute,every hour and on a daily basis

More modern miniature laser scanners weighing on the order of two andone-half pounds, such as described in U.S. Ser. No. 125,768, filed Feb.29, 1980, entitled "Portable Laser Scanning System and ScanningMethods," and assigned to the same assignee as the present application,have recently been proposed to provide a more truly portable laserscanning head which is supportable entirely by the user during thereading of the bar code symbols. Although generally satisfactory for itsintended purpose, this fully portable head had a rather large case widthdue to the fact that the laser beam generated within the head wasrequired to be swept over a wide field of view across the bar codedsymbol, which is located in the vicinity of a reference place locatedexteriorly of the housing. The swept laser beam, which was accommodatedentirely in the wide-bodied head, therefore, required a great deal of"dead" space within the head. This "dead" space caused the case width tobe unnecessarily large, and undesirably added to the overall size andweight of the head, thereby detracting somewhat from its features ofease of manipulation and full portability.

Another drawback of the wide-bodied head was that the case widthincreased from the rear towards the front the head, as considered in thedirection from the housing towards the reference plane, with the resultthat the front or nose of the head had a wide snout. In a preferredembodiment, the wide-bodied head had a gun-shaped configuration. It wasdesirable in some applications to insert the gun-shaped head, when notin use, into a user-supported holster of the kind traditionally used toreceive and support firearms. However, the wide snout on the wide-bodiedhead did not lend itself to conveniently fit in the traditional gunholster. Hence, the wide-bodied heads were typically tossed and left onthe nearest table, and were prone to being damaged, misplaced and lost.

Still another drawback associated with the semi-portable and wide-bodiedheads was that any dirt specks on the exit window through which thelaser beam exited en route to the bar code symbol, affected the laserscan at the symbol. The greater the distance between the exit window andthe symbol at the reference plane, the less of a potential malfunctionwould result from dirt specks on the exit window. However, the knownsemi-portable and wide-bodied heads were too dirt-sensitive for someapplications inasmuch as the exit window we too undesirably close to thereference plane.

SUMMARY OF THE INVENTION

1. Objects of the Invention

Accordingly, it is the general object of the present invention toovercome the aforementioned drawbacks of the prior art laser scanningheads.

Another object of this invention is to reduce the rather large casewidth heretofore required in prior art wide-bodied art laser scanningheads.

Still another object of this invention is to eliminate the amount ofdead space within the head.

Yet another object of this invention is to provide a laser scanning headwhich is so light-in-weight and small-in-volume, that it can be easilyheld in a user's hand without causing arm- and wrist-fatigue, whilebeing easy-to-manipulate, even for those assembly-line applicationswhere the user is routinely required to repetitively manipulate the headmany times per minute, every hour, and on a daily basis.

An additional object of this invention is to provide a fully portablelaser scanning head weighing on the order of one pound.

A further object of this invention is to eliminate the wide snoutheretofore present on prior art wide-bodied laser scanning heads.

Still another object of this invention is to provide a narrow-bodiedlaser scanning head which can readily be received and supported in atraditional V-shaped gun holster, thereby preventing possible damage to,and misplacement and loss of, the head.

Yet another object of this invention is to prevent dirt specks on thelaser exit window of the laser scanning head from adversely affectingthe reading of the bar code symbol.

A further object of this invention is to make the field of view of theincident laser beam traveling towards the symbol and/or the reflectedlaser beam traveling back from the symbol substantially independent ofthe case width of the head.

An additional object of this invention is to make the field of view ofthe incident laser beam and/or the reflected laser beam larger than thecase width of the head.

Still another object of this invention is to provide a twin-windowedlaser scanning head combining the advantages of optimum field of viewfor the incident laser beam, optimum field of view for the reflectedlaser beam, low spot speed scanning variation for the laser beam, lowsensitivity to dirt specks on the laser beam exit or scanning window,highlight sensor effectiveness, ease of judging scanning distance to thelight sensor, and minimum case width.

2. Features of the Invention

In keeping with these objects, one feature of this invention relates toa portable data collection terminal. The terminal includes a housing; akeyboard mounted on the housing for manual entry of data; a displaymounted on the housing for displaying information; a first printedcircuit board mounted within the housing; an integrated circuit storagechip for data collection mounted on the first printed circuit board; atransmitter for transmitting at radio frequency the collected datastored on the chip to a remote location away from the housing; and asecond printed circuit board mounted within the housing and on which thetransmitter is mounted.

In the preferred embodiment, the printed circuit boards are supportedtogether with each other as a unitary structure located within thehousing. A receiver is mounted on the second printed circuit board forreceiving radio frequency signals from the remote location.

It is advantageous when the housing has a top wall on which the keyboardand the display are mounted. The first and second printed circuit boardsare preferably arranged in mutually parallel relationship with the topwall.

Furthermore, a third printed circuit board is mounted within thehousing, in which case both the keyboard and the display includeelectronic drive circuitry on the third printed circuit board. Also, thetransmitter preferably includes an antenna mounted on the housing.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the followings description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view of a gun-shaped, narrow-bodied,twin-windowed embodiment of a laser tube-based portable laser scanninghead in accordance with this invention;

FIG. 2 is a partially broken-away, top sectional view of the embodimentof FIG. 1;

FIG. 3 is a rear sectional view as taken along line 3--3 FIG 1;

FIG. 4 is a top plan sectional view of a detail of the embodiment ofFIG. 1, showing the laser tube and part of the optical train;

FIG. 5 is a front elevational view of the embodiment of FIG. 1;

FIG. 6 is a front perspective view of the FIG. 1 embodiment, on a muchsmaller scale, and diagramatically shows the interconnection of the headto the remainder of the scanning system;

FIG. 7A is a top plan schematic view of a prior art wide-bodied head;

FIG. 7B is a top plan schematic view of an alternate, but unacceptable,design of a laser scanning head;

FIG. 7C is a top plan schematic view of another alternate, butunacceptable, design of a laser scanning head;

FIG. 7D is a top plan schematic view of the laser scanning head of FIG.1;

FIG. 8 is a side sectional view of a gun-shaped, narrow-bodied,twin-windowed embodiment of a laser diode-based portable laser scanninghead in accordance with this invention;

FIG. 9 is a partially sectioned, top plan view of the embodiment of FIG.8;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIGS. 1-6 of the drawings, reference numeral 10generally identifies a light-weight, narrow-bodied, streamlined,narrow-snouted, hand-held, fully portable, easy-to-manipulate,non-arm-and-wrist-fatiguing, twin-windowed laser scanning headsupportable entirely by a user for use in a laser scanning systemoperative for reading, scanning and/or analyzing bar code symbolsthroughout the reading thereof. Such symbols comprise a series of linesand spaces of varying widths, which pattern decodes to a multiple-digitrepresentation characteristic of the product bearing the symbol. Typicalsymbol bar codes in current use are the Universal Product Code (UPC),EAN, Codabar and Code 39.

Turning now to FIG. 1, the head 10 includes a generally gun-shapedhousing having a handle portion 12 and an elongated, narrow-bodiedbarrel or body portion 14. The handle portion 12 has a cross-sectionaldimension and overall size such that it can conveniently fit in the palmof a user's hand. Both the body and handle portions are constituted of alight-weight, resilient, shock-resistant, self-supporting material, suchas a synthetic plastic material. The plastic housing is preferablyinjection-molded, but can be vacuum-formed or blow-molded to form a thinshell which is hollow and bounds an interior space whose volume measuresless than a value which is on the order of 50 cubic inches. The specificvalue of 50 cubic inches is not intended to be self-limiting, but hasbeen provided merely to give an approximation of the overall maximumvolume and size of the head 10. The overall volume can be less than 50cubic inches and, indeed, in some applications, the volume is on theorder of 25 cubic inches.

The body portion 14 is generally horizontally elongated along alongitudinal axis, and has a front region 16 at the front end, a raisedrear region 18 at the rear end, and an intermediate body region 20extending between the front and rear regions. The body portion 14 has atop wall 11 above which the raised rear region 18 projects, a bottomwall 13 below the top wall, a pair of opposed side walls 15, 17 spacedtransversely apart of each other by a predetermined width dimension, afront wall or nose 19, and a rear wall 21 spaced rearwardly of the frontwall.

A light source means, i.e., laser tube 22 having an anode or output end23 (see FIG. 4) and a cathode or non-output end 25, is mounted withinthe body portion 14 lengthwise along the longitudial axis, and isoperative for generating an incident collimated laser beam. An opticmeans, i.e., an optic train, is likewise mounted within the bodyportion, and is operative for directing the incident beam along a lightpath towards a reference plane located exteriorly of the house in thevicinity of the front region 16, as show in FIGS. 1 and 2. A bar codesymbol to be read is located in the vicinity of the reference plane,that is, anywhere within the depth of focus of the incident beam asdescribed below, and the light reflected from the symbol constitutes areflected laser beam which is directed along a light path away from thereference plane and back towards the housing.

As best shown in FIGS. 4 and 5, the optic train includes an opticalbench 24, a negative or concave lens 26 which is fixedly mounted in acylindrical bore 25 of the bench, a light-reflecting mirror 26' which isfixedly mounted on an inclined surface 27 of the bench, anotherlight-reflecting mirror 28 which is fixedly mounted on another inclinedsurface 29 of the bench, a positive or convex lens 30 which isadjustably mounted on the bench by means of a set screw 31, and stillanother light-reflecting mirror 32 which is adjustably mounted on abendable metal bracket 33.

The optical bench 24 has an enlarged cylindrical recess 35 whichcommunicates with the smaller bore 25. The laser tube 22 is snuglyreceived in a cylindrical support sleeve 34 which, in turn, is snuglyreceived in the bore 25. An electrically conductive element or washer 36is located at the shoulder between the recess 35 and bore 25. The washer36 makes an electro-mechanical, non-soldered contact with the output end23 of the tube. Anther electrically conductive element, preferably aresilient wire 3B, is mounted at the non-output end 25 of the tube. Thewire 38 has one coiled end looped around the non-output end 25, anintermediate taut wire portion extending lengthwise of the tube, and itsother end is fixedly secured to the bench 24 by the set screw 37. Thewire 38 is preferably made of a resilient, spring-like material, and itstautness functions much like a spring or biasing means for affirmativelyurging the output end 23 into affirmative, electro-mechanical contactwith the washer 36. The non-output end 25 is grounded via the wire 38;and a high voltage power wire (not shown) from the power supplycomponent 40 mounted in the handle portion 12 is electrically connectedto a ballast resistor 42 mounted in another bore formed in the bench 24.The ballast resistor is, in turn, electrically connected to the washer36 by a wire, not illustrated for the sake of clarity. It will be notedthat neither the output nor non-output end of the tube is directlysoldered to any electrical wire, a feature which is highly desirable ineffecting on-site tube replacement. The bore 25 and recess 35 aremechanically bore-sighted so that the laser output beam is automaticallyoptically aligned with the optic train when the sleeve-supported tubeand output end are fully inserted into the recess 35 and bore 25,respectively.

The bench 24 is a one-piece light-weight part machined or preferablymolded by inexpensive mass-production techniques of a dimensionallystable, flame-retardant material, such as Delrin (Trademark), orglass-filled Noryl (Trademark), preferably having a high dielectricbreakdown (on the order of 500 volts/mil). In order to take into accountthe slight variations in bean alignment which unavoidably result fromdifferent tubes and from tolerance variations in the tube itself, thebore 25, and the recess 35, the very weak negative lens 26 (on the orderof -24 mm) is mounted very close to the output end of the tube, and allthe elements in the optical path are mace large enough to allow the beamto pass unobstructedly even if the beam is not exactly on center. Theclose mounting of the weak lens 26, and the short optical path (about 38mm) between lenses 26 and 30, mean that the optical tolerances in theremainder of the beam path can still be off by about 1/20 withoutsacrificing system performance. This provides the advantage that thebench can be

Thus, the beam emitted from the output end 23 first passes through thenegative lens 26 which functions to diverge the initially collimatedbeam. Then, the divergent beam impinges the mirror 26; and is thereuponreflected laterally to impinge the mirror 28, whereupon the beam isreflected upwardly to pass through the positive lens 30 which isoperative to converge the divergent beam to a generally circular spot ofapproximately an 8 mil to 10 mil diameter at the reference plane. Thespot size remains approximately constant throughout the depth of focusat either side of the reference plane. The converging beam from the lens30 impinges on the adjustable mirror 32, and is there-upon laterallyreflected to a scanning mirror 44 which forms part of the scanningmeans.

The scanning means is preferably a high-speed scanner motor 46 of thetype shown and described in co-pending U.S. Appl. Ser. No. 125,768,filed Feb. 29, 1980, entitled "Portable Laser Scanning System andScanning Methods," and assigned to the same assignee as the presentapplication. The entire contents of said application are incorporatedherein by reference and made part of this application. For purposes ofthis application, it is sufficient to point out that the scanner motor46 has an output shaft 41 on which a support plate 43 is fixedlymounted. The scanning mirror 44 is fixedly mounted on the plate 43. Themotor 46 is driven to reciprocally and repetitively oscillate the shaftin alternate circumferential directions over arc lengths of any desiredsize, typically less than 360°, and at a rate of speed on the order of aplurality of oscillations per second. In a preferred embodiment of thisinvention, the scanning mirror 44 and the shaft are jointly oscillatedso that the scanning mirror repetitively sweeps the beam impingingthereon through an angular distance A or an arc length of about 25° andat a rate of about 40 oscillations per second.

Stop means, i.e., an abutment 48, is fixedly mounted on a bracket 49which is, in turn, mounted on the bench 24. The abutment 48 is locatedin the path of oscillating movement of the plate 43 or the scanningmirror 44, for preventing the mirror from making a complete 360°rotation during shipping. The abutment never strikes the mirror duringscanning; the abutment serves to keep the mirror properly aligned, thatis, always facing towards the front of the head.

The scanning motor 46 is mounted on the bench 24 slightly offset fromthe longitudinal axis. Other miniature scanning elements can beutilized. For example, miniature polygons driven by motors can be used,or the various bimorph scanning oscillating elements described in U.S.Pat. No. 4,251,798 can be used, or the penta-bimorph element describedin the aforementioned co-pending application can be used, or theminiature polygon elements described in co-pending U.S. Appl. Ser. No.133,945, filed Mar. 25, 1980, entitled "Portable Stand-Alone Desk-TopLaser Scanning Workstation For Intelligent Data Acquisition Terminal andMethod of Scanning," and assigned to the same assignee as the presentapplication, the entire contents of which are hereby incorporated hereinby reference and made part of this disclosure, can be used.

Although only a single scanner element is shown in the drawings forcyclically sweeping the laser beam across the symbol along apredetermined direction (X-axis scanning) lengthwise thereof, it will beunderstood that another scanner element may be mounted in the head forsweeping the symbol along a transverse direction (Y-axis scanning) whichis substantially orthogonal to the predetermined direction. In someapplications, multiple line scanning is preferred.

Referring again to FIGS. 1 and 2, the scanning mirror 44 is mounted inhe light path of the incident beam at the rear region 18 of the head,and the motor 46 is operative for cyclically sweeping the incident beamthrough an angular distance A over a field of view across the bar codesymbol located in the vicinity of the reference plane. A laserlight-transmissive scan window 50 is mounted on the raised rear region18, behind an opening 51 formed therein in close adjacent confrontingrelationship with the scanning mirror 44 thereat. As used throughout thespecification and claims herein, the term "close adjacent confronting"relationship between components is defined to mean that one component isproximally located relative to the other component, typically less thanone inch apart of each other. As shown in FIG. 1, the scan window 50 isconfigured and positioned in the light path of the incident beam topermit the latter coming from the scanning mirror 44 to travel adistance of less than one inch within the raised rear region 18, andthen to pass through the scan window 50, and thereupon to travelunobstructedly and exteriorly of and past the intermediate body region20 and the front region 16 of the housing, and then to impinge on thesymbol located at or near the reference plane.

The closer the scanning mirror 44 is to the scan window 50, the largerwill be the field of view of the swept incident beam for a given scanangle. It will be noted that the width dimension of the scan windowrepresents a limiting factor for the sweep of the incident beam, becausethe housing walls bounding the scan window would clip and block any beamwhich was swept beyond the width of the scan window. Hence, as a rule,the scanning mirror is made as close as possible to the scan window tooptimize the field of view of the swept incident beam.

As best shown in FIG. 2, the field of view of the swept incident beam issubstantially independent of the width of the body portion 14 and, infact, the field of view, i.e., the transverse beam dimension, of theswept incident beam is actually larger than the width of the bodyportion 14 at the front region 16 and at the forward section of theintermediate body region 20. This is, of course, due to the fact thatthe swept incident beam has been transmitted outside of the front andintermediate body regions of the housing. The side walls 15, 17 are notin the light path and do not clip or block the swept incident beam. Thescan window 50 is mounted on the rear region 18 at an elevation abovethe top wall 11 to permit an overhead unobstructed transmission.

In a preferred embodiment, the width of the body portion 14 is on theorder of 13/4 inches, whereas the field of view at the reference planeis on the order of 31/2 inches. In prior art wide-bodied designs, thewidth of the housing was greater than 31/2 inches in order to obtain a31/2 inch field of view for a given scan angle. Hence, the exteriortransmission of the swept incident beam permits the head of the presentinvention to have a narrow-bodied streamlined configuration. The sidewalls 15, 17 need no longer diverge outwardly towards the front as inprior art designs to accommodate the swept beam, but can be madesubstantially parallel as shown, or in any other shape as desired.

In a preferred embodiment, the reference plane is located about 2 inchesfrom the front wall 19 of the head, and is located a linear distance ofabout 91/2 inches from the positive lens 30. The depth of field at thereference plane is about 23/4" on either side of the reference plane.These numerical figures are not intended to be self-limiting, but aremerely exemplary.

A laser light-transmissive non-scan window 52 is mounted on the frontwall 19 in close adjacent confronting relationship with the sensor means54 located at the front region 16. The sensor means 54 is operative fordetecting the intensity of the light in the reflected beam coming fromthe symbol over a field of view across the same, and for generating anelectrical analog signal indicative of the detected light intensity. Inorder to increase the zone of coverage of the sensor means, a pair ofsensor elements or photodiodes 54a, 54b are located on opposite sides ofthe longitudinal axis. The sensor elements lie in intersecting planesand face both forwardly and laterally. The front wall 19 is likewiseconstituted of a pair of tapered wall portions 19a, 19b, each of whichhas an opening 53a, 53b formed therein. A pair of non-scan windowportions 52a, 52b is fixedly mounted behind the openings 52a, 52b,respectively. Each non-scan window portion is mounted in close adjacentconfronting relationship with its respective sensor element. Thenon-scan window portions are configured and positioned in the light pathof the reflected beam to permit the latter to pass therethrough to thesensor elements. Two small non-scan window portions are preferablyutilized, rather than a single non-scan window, because two smallerwindows are inherently stronger than one due to the greater perimeterthat two windows provide.

The scan window 50 is located rearwardly of the non-scan window 52. Eachwindow 50, 52 is located at a different distance from the referenceplane and the front wall 19. The scan window 50 is elevated above thenon-scan window 52, as described above. The non-scan window portions arelocated at opposite sides of the longitudinal axis. The scan window islocated on the longitudinal axis.

A printed circuit board 59 is mounted within the body portion 14, andvarious electrical sub-circuits diagrammatically represented byreference numerals 55, 56, 57, 58 are provided on the board 59. Signalprocessing means 55 is operative to process the analog signal generatedby the sensor elements to a digitized signal to generate therefrom datadescriptive of the bar code symbol. Suitable signal processing means forthis purpose was described in U.S. Pat. No. 4,251,798. Sub-circuit 56constitutes drive circuitry for the scanner motor 46. Suitable motordrive circuitry for this purpose was described in the aforementionedco-pending application Ser. No. 125,768. Sub-circuits 57 and 58constitute a safety circuit for the laser tube, and voltage regulatorcircuitry. Suitable circuitry for this purpose were also described inco-pending application Ser. No. 125,768.

Shock mounting means are mounted at the front and rear regions of thebody portion, for shock mounting the laser, optical and scanningcomponents within the body portion. An annular shock collar 60,preferably of rubber material, surrounds the forward end of the tube 22and engages the bottom wall 13 and the under-side of the circuit board59. Board support elements 61a, 61b extend downwardly of the top wall 11to rigidly support the circuit board 59. A pair of rubber shock mounts62, 64 are fixedly mounted on opposite sides of the optical bench 24,and respectively engage the side walls 15, 17 at the rear region 18 ofthe housing. The shock mounts 62, 64 and the collar 60 are spacedlongitudinally apart of each other and engage the thin-walled housing athree spaced locations to isolate twisting of the housing from thelaser, optical and scanning components.

Electrical power is supplied to the laser tube 22 by the power supplycomponent 40 mounted within the handle portion 12. The power supplycomponent which steps up a 12 vDC battery voltage to over 1 kilovolt isthe heaviest component in the head, and its mounting in the handleportion allows for a low center of gravity and for better balance of thehead.

A non-bulky, collapsible, coil-type cable 66 (see FIG. 6) electricallyconnects the head 10 to the remainder of the scanning system, whichincludes a battery-powered decode module 68 and a host computer 70. Thecoil-type cable 66 is readily flexible and permits user manipulation ofthe head 10 with multiple freedoms of movement from one symbol to thenext without requiring excessive strength by the user. The cable 66includes a plurality of conductive wires which are all relatively thinand flexible. For example, one wire carries the 12 vDC low voltagesignal from the battery in the decode module 68 to the power component40. Another wire carries the digitized signal from the analog-to-digitalsignal processing circuitry 55 to the decode module 68 for decodingpurposes. This latter wire is non-radio-frequency-shielded, and hence,is readily flexible. The remaining wires carry low voltage control andcommunication signals. All of the wires of the cable 66 are connectedtogether to a common plug-type connector 72. A mating connector 74 ismounted within the head, and receives the connector 72 in a matingrelationship. The use of the mating connectors 72, 74 permits rapidreplacement of the cable or on-site repairs. The electrical connectionsbetween the connector 74 and the various components in the head havebeen omitted from the drawings for the sake of clarity.

The decode module 68 processes the digitized signal generated in thehead, and calculates the desired data, e.g. the multiple digitrepresentation or code of the bar code symbol, in accordance with analgorithm contained in a software program. The decode module 68 includesa PROM for holding the control program, a RAM for temporary datastorage, and a microprocessor which controls the PROM and RAM and doesthe desired calculations. The decode module also includes controlcircuitry for controlling the actuatable components in the head asdescribed below, as well as two-way communications circuitry forcommunicating with the head and/or with the host computer 70. The hostcomputer 70 is essentially a large data base, and provides informationfor the decoded symbol. For example, the host computer can provideretail price information corresponding to the decoded symbols.

A manually actuatable trigger switch 56 is mounted on the head in theregion where the handle portion 12 is joined to the body portion 14.Depression of the trigger switch 76 is operative to turn themicroprocessor in the decode module on. Upon release of the triggerswitch, the spring 78 restores the switch to its initial position, andthe microprocessor is turned off. In turn, the microprocessor iselectrically connected to the actuatable components in the head via thecable 66 to actuate and deactuate the actuatable components when themicroprocessor is respectively turned on or off by the trigger switch.

In prior art heads, the trigger switch was only operative to turn thelaser tune and/or scanner motor on or off. Now, the trigger switch turnsthe microprocessor on or off and, in turn, all of the actuatablecomponents in the head on or off. The micro-processor is a large powerdrain on the battery built into the decode module. Hence, by controllingthe on-time of the microprocessor to only those times when a symbol isbeing read, that is, when the trigger switch is depressed, the powerdrain is substantially reduced, and the battery life substantiallyincreased (over 5 hours).

Another feature of this invention is embodied in turning themicroprocessor on or off by means of the host computer 70 which isremote from the head 10. The computer 70 typically includes a keyboardand a display. Once a user makes an entry on the keyboard for example,by entering the identity of the code to be decoded, the computerrequests the microprocessor to turn itself on, store the information,and then to turn the microprocessor off. The microprocessor, again, ison only for so long as is necessary to comply with the computer request.The trigger switch and the keyboard computer entry are independentlyoperable means for directly controlling the microprocessor, and forindirectly controlling the actuatable components in the head.

Another useful feature in having the microprocessor, rather than thetrigger switch, directly control the laser tube is to keep an accuraterecord of laser on-time for governmental recordkeeping. It is, ofcourse, far easier to keep track of laser on-time in the software of amicroprocessor than to manually record the laser on-time.

A set of visual indicators or lamps 80, 82, 84 is also mounted on thecircuit board 59, each lamp being positioned below a correspondingopening in the top wall 11. The lamps are operative to visually indicateto the user the status of the scanning system. For example, lamp 80illuminates whenever the laser tube is energized, thereby continuouslyadvising the user whether the tube is on or off. Lamp 82 illuminateswhen a successful decode has been obtained. It will be recalled that theincident beam is swept over a symbol at a rate of about 40 scans persecond. The reflected beam may be successfully decoded on the firstscan, or on any of the successive scans. Whenever a successful scan hasbeen obtained, the microprocessor will cause the lamp 82 to beilluminated to advise the user that the head is ready to read anothersymbol.

It is believed that the operation of the scanning system is self-evidentfrom the foregoing, but by way of brief review, the gun-shaped head isgrasped by its handle portion, and its barrel is aimed at the bar codesymbol to be read. The sighting of the symbol is facilitated by the factthat the barrel is narrow-bodied, and that there are no obstructions onthe front and intermediate body regions of the barrel. The front wall ofthe barrel is situated close to the symbol, it being understood that thesymbol can be located anywhere in the depth of field at either side ofthe reference plane.

The trigger switch is then depressed, thereby causing the microprocessorto energize the laser tube, the scanner motor, the sensor elements, andall the electronic circuitry provided on the printed circuit board. Thelaser tube emits a beam, which is then routed through the optic train asdescribed above, and thereupon, the scanning mirror reflects the beamthrough the scan window and out of the head exteriorly of and past thefront and intermediate body regions of the body portion of the head. Thereflected beam passes through the non-scan window portions to the sensorelements and is subsequently processed by the signal processingcircuitry. The processed signal is conducted to the decode module fordecoding. Once a successful decode has been realized, the microprocessorilluminates the lamp 82 and deactuates the head, and the user is nowadvised that the head is ready to be aimed at another symbol. Theflexibility of the coil-type cable facilitates the movement of the headto the next symbol.

In addition, the movement of the head from one symbol to the next isfacilitated by the relatively low weight of the head. The head with allthe aforementioned components therein weighs less than one pound. Thisrepresents a significant breakthrough in the art of miniaturized andportable laser scanning heads.

The twin-windowed head (the pair of non-scan window portions 52a, 52bconstitutes one non-scan window 52; the scan window 50 constitutes theother window) with the rear, raised scan window 50 overcomes severalproblems associated with the prior art heads. To facilitate theexplanation of these problems and how the twin-windowed head of thisinvention solves these problems, the top plan schematic views of FIGS.7A, 7B, 7C, 7D have been provided. FIG. 7A diagrammatically illustratesa prior art wide-bodied head of the type shown in the aforementionedco-pending application U.S. Ser. No. 125,768. FIGS. 7B and 7Cdiagrammatically illustrate some head design alternatives, but which areunacceptable, because they fail to solve all of the prior art problems.FIG. 7D diagrammatically illustrates the narrow-bodied, twin-windowedhead of the present invention, as previously described in FIGS. 1-6.

FIG. 7A shows an elongated body portion or barrel 86 having a rearscanning means 44, 46, as described above, operative to sweep anincident beam through a scan angle A of predetermined arc length, e.g.,25°, through a single front window 92. The reflected beam also passesthrough the front window 92 to be detected by the sensor elements 54a,54b, also described above. The barrel is relatively wide-bodied toaccommodate the swept incident beam within the barrel, and the front ofthe housing is relatively close to the reference plane.

As compared to FIG. 7A, FIG. 7B shows a narrower barrel 88 having a moreforwardly scanning means 44, 46 operative for sweeping the incident beamthrough a larger scan angle B, e.g. on the order o 45°, through a singlefront window 94. The reflected beam also passes through the front windowto be detected by the sensor elements 54a, 54b. The front of the housingis spaced further from the reference plane.

As compared to FIG. 7B, the scanning means 44, 46 in FIG. 7C is locatednear the middle of the barrel 90, and is operative to sweep the incidentbean through the original 25° scan angle through the single front window96. The reflected beam also passes through the front window fordetection by the sensor elements 54a, 54b. The front of the housing isspaced much further from the reference plane.

FIG. 7D needs no detailed description, except to repeat that the rearscanning means 44, 46 has its scan window 50 rearwardly located on thehousing. The scan window 50 is raised so that the swept incident beam isnot accommodated within, the barrel 14. The reflected beam passesthrough a different window, i.e., the non-scan window 52 located at thefront of the barrel.

In rating the performance of a laser scanning head, the spot speedvariation of the scan across the symbol should ideally be constant sothat the signal processing circuitry can be simple, i.e., withoutrequiring sophisticated circuitry to compensate for the spot speedvariation. By way of example, the spot speed at point X in the depth offield C is much greater than the spot speed at point Y. It is well knownthat the lower the scan angle A, the lower will be the projected spotspeed variation. Hence, a 25° scan angle as illustrated in FIGS. 7A, 7C,7D is better in terms of spot speed variation than the 45° scan angle ofFIG. 7B.

As noted above, the problem of dirt specks on the scan or exit windowadversely affects the scanning ability, particularly where the window ispositioned in the light path, where the scan spot is focused andrelatively small. Hence, the greater the spot size and concomitantly thegreater the distance between the exit window and the reference plane,the better the scanning performance. Hence, the head of FIG. 7D with itsrear exit window 50 the furthest from the reference plane has the leastsensitivity to dirt specks, and the heads of FIGS. 7C, 7B, 7A aresuccessively more sensitive to dirt specks.

In terms of light sensor effectiveness, the closer the sensor elementsare to the reference plane, the more sensitive will be the detection bythe sensor elements. Hence, the heads of FIGS. 7D and 7A have the bestlight sensitivity; the head of FIG. 7B has less light sensitivity; andthe head of FIG. 7C has the worst light sensitivity.

In operation, it is easier for a user to gauge a working distance closeto the head, rather than a working distance located far therefrom.Typically, it is easier for the user to aim the head at a symbollocated, for example, anywhere between 1/4" and 6" away from the frontwall of the barrel, rather than aim the head at a symbol located, forexample, between 9" and 12" from the front wall. Hence, the heads ofFIGS. 7D and 7A are the best in terms of user convenience; the head ofFIG. 7B is less convenient; and the head of FIG. 7C is the mostinconvenient.

Of great importance is the effect that the barrel width has on the widthof the scan. As shown in FIG. 7A, the entire width of the scan must beaccommodated in the barrel 86, thereby resulting in a wide-bodied,unaesthetic design. If the scanner means is moved forwardly as shown inFIG. 7B so as to narrow the width of the barrel, then the scan anglemust be increased to obtain the same field of view. As noted above,increasing the scan angle is no, an acceptable solution, because itworsens the spot speed variation performance. If the scanner means ismoved rearwardly back towards the middle of the barrel, and the scanangle is kept at its original arc length, and the body is kept narrow,as shown in FIG. 7C, then the light sensor effectiveness will worsen,and the convenient judgment of scan distance will worsen.

In a non-retro-reflective mode, the applicants have recognized that theuse of a single front window through which the incident and reflectedbeams must pass has conflicting requirements. By providing a rear windowand a front window for the beams, these conflicting requirements areresolved. The head of FIG. 7D has the best insensitivity to dirt speckson the exit window, has the narrowest barrel width, and has optimumcontrol over spot speed variation, optimum ease of judging scandistance, and optimum light sensor effectiveness.

In accordance with the invention, the housing need only be large enoughto accommodate the components. This benefits styling, cost and weight.The scan width may be varied from one application to the next withoutmaking a change in the barrel. By mounting the scanning means close tothe rear scan window, the field of view of the incident beam is madevery wide. Analogously, by mounting the sensor means close to the frontnon-scan window, the field of view of the reflected beam is made verywide. Furthermore, the close mounting of the scanning and sensor meansto their respective windows, eliminates the prior art narrow slitaperture, and eases optical alignment of the incident beam, and avoidspotential clipping of the incident beam if the beam angle drifts.

Referring now to FIGS. 8 and 9, the gun-shaped head 100 is essentiallyanalogous to the head 10, except as noted below. Hence, any likecomponents in FIGS. 8 and 9 have been identified with the same referencenumerals as were used previously. Rather than a laser tube, asemiconductor laser diode 102 is mounted within the barrel 14 togenerate an incident laser beam. Rather than a folded path opticaltrain, an optics tube 104 is axially aligned with the laser diode. Alight-reflecting mirror 106 is adjustably mounted on a bendable bracket108 that is mounted on the exterior of the tube 104. The mirror 106 ispositioned in the light path of the incident beam to direct the incidentbeam towards the scanning mirror 44 of the scanner motor 46. Asdescribed previously, the motor 46 is operative to sweep the incidentbeam through the rear scan window 50 and outside of the barrel 14 pastthe intermediate body region 20 and front region 16 thereof. Thereflected beam passes through the non-scan window 52 to the sensor means54 for detection and subsequent processing as previously described.

A keyboard 110 and a display 112 are mounted on the top wall 11 of thebarrel. The keyboard 110 comprises a plurality of manually-depressablekeys each for a different numeral, and a set of function keys tocalculate and display various functions required in a given application.The display 112 may be of the low power LCD type. By mounting thedisplay 112 and the keyboard 110 on the head 100, this featurefacilitates keyboard entry and data reading at the site of the symbol tobe read, rather than at a more remote location away from the head.

Inasmuch as the laser diode 102 does not require a voltage step-upcomponent 40, but can be energized directly from a low voltage battery,a battery 114 is mounted within the handle 12 to energize the diode. Inorder to even further facilitate the movement of the head 100 relativeto the remainder of the system, the aforementioned cable 66 is totallyeliminated. In its place, a transmitting antenna 116 may be mounted atthe rear of the handle, and is operative to electromagnetically transmitthe processed information to the remainder of the system. In addition tocircuit board 59, another circuit board 118 is provided within thebarrel to accommodate the additional electronic circuitry for thekeyboard and the display.

Still another circuit board 120 is mounted within the barrel toaccommodate a radio transmitter 124 and a frequency shift key modulator125. The modulator 125 will place one or another tone (frequency) on theradio wave generated by the transmitter 124 and telemetered over theantenna 116. In one embodiment of the invention, the telemetered signalcorresponds to the digitized signal generated in the head, and thetelemetered signal is received by a receiver and a demodulator, whichare incorporated in the decode module 68. In this case, the decodemodule 68 must also have a return transmitter and a modulator forelectromagnetically telemetering the decoded information back to thehead 100, where the decoded information is then received and demodulatedby a return receiver 126 and a demodulator 127, which are also mountedon circuit board 120. The decoded information can be displayed ondisplay 112.

In another embodiment of the invention, the entire decode module 68 maybe reduced by large scale integration to one or two integrated circuitchips, e.g. chips 128, 129, which are mounted on yet another printedcircuit board 122 provided in the barrel. In this case, the digitizedsignal generated by sub-circuit 55 is decoded by chips 128, 129 right inthe head 100, rather than at some location remote from the head. Hence,the telemetered signals corresponds to the decoded signal generated inthe head, and the telemetered signal is transmitted not to a remotedecode module, but directly to the host computer 70, which must nowinclude a receiver and a demodulator for the decoded signal. Of course,the host computer must also include a return transmitter and a modulatorfor electromagnetically telemetering the desired data back to the head100, where the data is then received and demodulated by the returnreceiver 126 and the demodulator 127. The data can be displayed ondisplay 112.

The laser scanning head 100 shown in FIGS. 8 and 9 constitutes acomplete and independent data processing workstation in the sense thatit is fully portable; it is battery-powered; it decodes the symbol inthe head; and it is not mechanically connected to any remote systemcomponent. The head 100 is readily adaptable to interact with any hostcommuter.

As noted previously, the host computer or terminal 70 is a data base,and may be incorporated in a built-in large computer installation; orcan be made smaller and constitute a light-weight, hand-held, discreteunit. As shown in FIGS. 8 and 9, an integrated circuit storage chip 129'is mounted within the head 100 on board 122 to form a complete datacollection terminal which facilitates real-time and subsequent dataprocessing with the computer 70 at the site of the symbol to be read. Asdescribed above, the interconnection between the module 68 and computer70 can be hand-wired, or by means of telemetry, or by plug-inconnection.

While the invention has been illustrated and described as embodied in anarrow-bodied, single-and twin-windowed, portable laser scanning headfor reading bar code symbols, it is not intended to be limited to thedetails shown, since various modifications and structural changes may bemade without departing in any way from the spirit of the presentinvention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

We claim:
 1. A portable data collection terminal, comprising:a) ahand-held housing including a main portion having a top wall portionlying in a predetermined plane, and a handle portion configured to beheld in an operator's hand during data collection; b) a keyboard mountedon the top wall portion of the housing within ready access of theoperator, for manual entry of data; c) a display mounted on the top wallportion of the housing adjacent the keyboard within ready visibility ofthe operator, for displaying information; d) a first printed circuitboard mounted within the main portion of the housing; e) an integratedcircuit storage chip for data collection mounted on the first printedcircuit board; f) a transmitter for transmitting at radio frequency atransmitted signal representative of collected data stored on the chipvia an antenna to a processor at a remote location away from thehousing; g) a modulator for modulating the transmitted signal; h) areceiver for receiving at radio frequency a modulated return signal fromthe processor; i) a demodulator for demodulating the modulated returnsignal; j) a second printed circuit board mounted within the mainportion of the housing and on which the transmitter, receiver, modulatorand demodulator are mounted, said first and second circuit boards lyingin generally parallel respective planes that are parallel to thepredetermined plane of the top wall portion; and k) a battery supportedby the housing within the handle portion, for supplying electrical powerto the keyboard, display, storage chip, the transmitter, receiver,modulator and demodulator.
 2. The terminal according to claim 1, whereinthe keyboard has a number of depressible keys arranged in mutuallyorthogonal rows and columns on the top wall portion of the housing. 3.The terminal according to claim 1, wherein the display includes a liquidcrystal display.
 4. The terminal according to claim 1, wherein theantenna is supported exteriorly on, and extends away from, the handleportion.
 5. The terminal according to claim 1; and further comprising acontrol chip mounted on the first circuit board, for processing datastored on the storage chip.
 6. The terminal according to claim 1; andfurther comprising a third printed circuit board mounted within the mainportion of the housing, and further comprising electronic drivecircuitry mounted on the third circuit board for driving the keyboardand the display.
 7. The terminal according to claim 6, wherein thefirst, second and third circuit boards are in mutual parallelism.
 8. Theterminal according to claim 7, wherein the top wall portion liesgenerally parallel to the first, second and third circuit boards.